CN103048423A - Method for testing influence on gelatinizing property of fracture plugging agent - Google Patents
Method for testing influence on gelatinizing property of fracture plugging agent Download PDFInfo
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- CN103048423A CN103048423A CN 201110325986 CN201110325986A CN103048423A CN 103048423 A CN103048423 A CN 103048423A CN 201110325986 CN201110325986 CN 201110325986 CN 201110325986 A CN201110325986 A CN 201110325986A CN 103048423 A CN103048423 A CN 103048423A
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Abstract
The invention discloses a method for testing the influence on the gelatinizing property of a fracture plugging agent. The method comprises the steps of: a, preparing a fracture plugging agent solution; b, then adding a pre-crosslinking agent and an accelerant, wherein the pre-crosslinking concentration ratio is 40:1, and the concentration of the accelerant is 3mg/L; c, adding secondary crosslinking agents with different concentrations; d, respectively testing the system gelatinizing time and the gelatinizing strength of the fracture plugging agent at a certain temperature; and e, analyzing the influence of the concentration of the secondary crosslinking agent on the gelatinizing time and the gelatinizing strength of the fracture plugging agent according to tested data. The method is capable of rapidly testing the influence of the concentration of the secondary crosslinking agent on the gelatinizing time of the fracture plugging agent, is accurate in testing result, simple in testing steps, and low in testing cost, and provides data support for the synthesis of the fracture plugging agent.
Description
Technical field
The present invention relates to a kind of method for the impact of mini-frac blocking agent gel-forming property.
Background technology
Low-permeability oil deposit is to refer generally to the oil reservoir that the oil reservoir of permeability between 10-50 * 10-3 μ m2 consists of in China.Along with the continuous intensification of exploration and development degree, China's low-permeability oil pool total proven reserves and in the mining-employed reserves shared ratio more and more higher, keep and the promotion development of oil industry in the effect brought into play increasing.As take China National Petroleum Corporation (CNPC) as example, at the bottom of calendar year 2001, verify petroleum-in-place 145 * 108t, wherein hyposmosis reserves 44 * 108t accounts for 30%; Employ petroleum-in-place 110 * 108t, wherein hyposmosis reserves 21 * 108t accounts for 19%; Residue is verified and is not employed petroleum-in-place 35 * 108t, and wherein hyposmosis reserves 22 * 108t accounts for 62%.In the reserves of verifying then in the recent period, the shared ratio of hyposmosis reserves is larger, up to 65%～70%.How to employ and developed the low permeability oil field reserves, to the sustainable and stable development of China Petroleum with guarantee that the safe tool of China's oil is of great significance.
Low-permeability oil deposit is because reservoir properties is poor, and oil well output is low, and owing to complex pore structure, seepage state is unusual, causes its oil-field development feature and medium to high permeable oil reservoir to be very different, even the variation of matter occurs.LOW PERMEABILITY OILFIELD DEVELOPMENT has following essential characteristic:
(1) the oil well natural production capacity is low, just has commercial mining behind the fracturing reform and is worth;
(2) percolation law is not followed Darcy's law, has the starting pressure gradient;
(3) natural energy is little, and pressure, production declining are fast, and primary recovery rate is low;
(4) the water injection well water-intake capacity is low, and starting pressure and water injection pressure rise fast;
(5) liquid production index sharply descends behind the oil well water breakthrough, and the stable yields difficulty is very large.
Hydraulic fracturing technology has been widely used in the exploitation in low-permeability oil gas field as the major measure of well production increment, intensified injection of wells, for the stable yields of oil gas field has been made significant contribution.Improve near the seepage flow condition the shaft bottom by waterfrac treatment, linked up the oil gas gathering area and change the hydrocarbon flow flowing mode, improved Oil ﹠ Gas Productivity.The output of domestic hypotonic oil gas field and the output that obtains by the waterfrac treatment transformation are all increasing sharply year by year.
Through oil, gas, the well after the waterfrac treatment, owing to be subjected to the at that time restriction of fracturing technology, material, equipment tool, the reason such as it is little that scale is owed, and material selection is improper, and plant capacity is limited can cause the hydraulic fracture flow conductivity significantly to reduce and ineffective gradually; Some then selects improper because of the well layer or the operation reasons also fails effectively to pass through simultaneously long period of development, and the major oil gas field has entered the development phase of middle and high Water-cut Period, and the difficulty of stable high yield is increasing; To this class Oil/gas Well, in order to obtain high yield and economic exploitation benefit, need to carry out refracturing.
Refracturing refers to the well layer of taking once or several times pressing crack construction measure is implemented fracturing reform again.As far back as the 1950's, just carried out refracturing abroad, development through more than 50 years, reservoir reevaluating, well and story selecting new technology, fracturing liquid, fractured well performance prediction, refracturing crack steering mechanism, refracturing optimal design and the aspects such as technology research, crack Diagnosis and effect assessment all are rapidly developed before refracturing, not only become the increasing yield and injection means of hydrocarbon-bearing pool, also become economical and effective and develop gordian technique hypotonic, ultra-low permeability reservoir.
Hydraulic fracturing technology is applied to the exploitation in low-permeability oil gas field, begins to have so far more than 50 year from nineteen forty-seven.Become with regard to technology that hyposmosis and extra-low permeability Reservoir Development are indispensable, ripe and effective petroleum engineering technology.
Have different hydrocarbon reservoirs in order to solve better, the oil gas field of exploitation and exploitation characteristics is at the different phase Main Problems, hydraulic fracturing technology is also constantly proposing new approaches and is developing new method.
At that time technology and level of understanding restriction just begun refracturing research abroad as far back as the sixties, owing to it is generally acknowledged that refracturing is the further extension of original hydraulic fracture or again opens closed hydraulic fracture.The mid-80, along with oil gas price changes and the development of modern hydraulic fracturing technology, abroad (mainly being the U.S.) again with refracturing as an important technical research problem, possibility, the refracturing of managing and make new seam from refracturing assessment, refracturing seam producing machine select well to comment the aspects such as a layer principle, refracturing design and construction to carry out theoretical research and field experiment analysis, make multiple fracturing technique obtain a series of major progresses.
USDOE in 1987 change the pressure break experiment of stress in many wells experiments, first proved stress field be subject to the impact of offset well crack.Dowell company is thought according to experiment and simulated ground stress research, exist supporting crack will change near the stress distribution of well in the stratum, make the crack initiation orientation of refracturing perpendicular to first crack, leave to redirect to again after the well certain limit and be parallel to first fracture azimuth and extend.Chen﹠amp; The researchs such as Minner are thought that pore pressure changes and are caused new crack approximately perpendicular to crack last time or with last time the crack was in an acute angle.Chevron Oil Tech Inc shows in the test in U.S. Lost Hill oil field, refracturing fracture azimuth and 30 ° of first fracture orientation skews; Unocal company has confirmed that in the test of the refracturing in Van oil field the refracturing crack may depart from 60 ° with fracture azimuth last time.The development of multiple fracturing technique that these have tested the promotion strong with research has obtained extremely significant economic benefit.For example, Rangely oil field, one of oil field that the U.S. develops the earliest, many well refracturings reach 4 times, and success ratio reaches 70-80%; Refracturing is 185 mouthfuls in 385 mouthfuls of producing wells in Kuparuk River oil field, U.S. Alaska, and productivity index has on average improved twice after pressing.
A large amount of refracturing operations has also been carried out in the oil fields such as recent year grand celebration, triumph, long celebrating, huge port, Jilin, and has done certain exploration from theory and practice, has obtained some experiences and understanding.Since nineteen ninety-five, Southwest Petrol University has successively carried out STUDY ON REPETITIVE FRACTURING TECHNOLOGY with Liaohe Oil Field, long celebrating oil field, Xinjiang Oilfield and Shengli Oil Field, and with the changed course refracturing test that has launched the new seam of the stifled old seam pressure of high water-cut stage in length celebrating oil field, the Xinjiang Oilfield cooperation, obtain good effect of increasing production, opened up the new direction of refracturing research.
The process of stifled pressure integrated technique is to use first the long-acting shutoff of blocking agent or the temporary transient old crack of shutoff, and then other orientation presses off new crack on the stratum with waterfrac treatment technique, again transforms reservoir to reach, and improves the purpose of reservoir recovery.Behind the blocking agent shutoff crack, follow-up fracturing liquid must have extruding and penetration to it, therefore requires the refracturing blocking agent to have the performance higher than conventional blocking agent.
After entering old crack, refracturing blocking agent working fluid forms gel, under follow-up fracturing liquid effect, blocking agent will be subject to of the fracturing fluid extruding and penetration, therefore the performance of refracturing blocking agent will satisfy the requirement of two aspects: the one, and the strongly adherent between blocking agent-crack wall stops fracturing liquid to penetrate toward first man-made fracture; The 2nd, self has high strength blocking agent, can resist of the fracturing fluid extruding.Blocking agent not only has high intensity and adhesiveness in a word, and certain stress deformation ability will be arranged.This just requires the breakthrough pressure of blocking agent will be higher than the extruding force that is subject to.
In addition, what stifled old seam blocking agent faced is crack problem, and blocking agent also needs to satisfy leak-off low in the crack to guarantee the one-tenth colloidality matter that it is good and to reduce injury to matrix, so should take secondary to become the glue technology.Secondary becomes glue to refer to blocking agent gel a little less than ground is pre-formed lower crosslink density, claims " pregel " or a gel, after one time gel injects the stratum, again is cross-linked to form high-strength gel, i.e. two-step gelation under the reservoir temperature condition.
The secondary cross-linking agent concentration has very large impact to gelation time and the gelling strength of pressure break blocking agent, how to determine fast and accurately the impact of secondary cross-linking agent concentration comparison pressure break blocking agent gelation time and gelling strength, the synthetic of pressure break blocking agent seemed most important.
Summary of the invention
The object of the invention is to overcome the shortcoming and defect of above-mentioned prior art, a kind of method for the impact of mini-frac blocking agent gel-forming property is provided, the method can test out the secondary cross-linking agent concentration fast on the impact of pressure break blocking agent gelation time, and test result is accurate, testing procedure is simple, testing cost is low, and the synthetic Data support that provides of pressure break blocking agent is provided.
Purpose of the present invention is achieved through the following technical solutions: a kind of method for the impact of mini-frac blocking agent gel-forming property may further comprise the steps:
(a) configuration pressure break blocking agent solution;
(b) then add precrosslinker and promoter, and the poly-double ratio of precrosslink is 40: 1, promoter concentration 3mg/L;
(c) the secondary cross-linking agent of adding variable concentrations;
(d) record respectively at a certain temperature system gelation time and the gelling strength of pressure break blocking agent;
(d) analyze the secondary cross-linking agent concentration to the impact of pressure break blocking agent gelation time and gelling strength by data measured.
In the described step (a), the environment temperature of configuration pressure break blocking agent solution is 28 ℃.
In the described step (a), by clear water configuration pressure break blocking agent solution.
In the described step (d), probe temperature is 85 ℃.
In sum, the invention has the beneficial effects as follows: can test out fast the secondary cross-linking agent concentration to the impact of pressure break blocking agent gelation time, and test result is accurate, testing procedure is simple, and testing cost is low, and the synthetic Data support that provides of pressure break blocking agent is provided.
Embodiment
Below in conjunction with embodiment, the present invention is described in further detail, but embodiments of the present invention are not limited only to this.
Embodiment:
A kind of method for the impact of mini-frac blocking agent gel-forming property that the present invention relates to, its concrete steps are as follows:
(a) configuration pressure break blocking agent solution;
(b) then add precrosslinker and promoter, and the poly-double ratio of precrosslink is 40: 1, promoter concentration 3mg/L;
(c) the secondary cross-linking agent of adding variable concentrations;
(d) record respectively at a certain temperature system gelation time and the gelling strength of pressure break blocking agent;
(d) analyze the secondary cross-linking agent concentration to the impact of pressure break blocking agent gelation time and gelling strength by data measured.
In the described step (a), the environment temperature of configuration pressure break blocking agent solution is 28 ℃.
In the described step (a), by clear water configuration pressure break blocking agent solution.
In the described step (d), probe temperature is 85 ℃.
The present invention is split blocking agent with 50 sub-very much piezometrics, fixedly host concentration 4%, and the poly-double ratio of precrosslink 40: 1, promoter concentration 3mg/L change the secondary cross-linking agent concentration, observe system gelation time and gelling strength situation of change under 85 ℃ of temperature, as shown in the table by the result that said method records:
The above only is preferred embodiment of the present invention, is not the present invention is done any pro forma restriction, and every foundation technical spirit of the present invention, any simple modification, equivalent variations to above embodiment does all fall within protection scope of the present invention.
Claims (4)
1. a method that is used for the impact of mini-frac blocking agent gel-forming property is characterized in that, may further comprise the steps:
(a) configuration pressure break blocking agent solution;
(b) then add precrosslinker and promoter, and the poly-double ratio of precrosslink is 40: 1, promoter concentration 3mg/L;
(c) the secondary cross-linking agent of adding variable concentrations;
(d) record respectively at a certain temperature system gelation time and the gelling strength of pressure break blocking agent;
(d) analyze the secondary cross-linking agent concentration to the impact of pressure break blocking agent gelation time and gelling strength by data measured.
2. a kind of method for the impact of mini-frac blocking agent gel-forming property according to claim 1 is characterized in that, in the described step (a), the environment temperature of configuration pressure break blocking agent solution is 28 ℃.
3. a kind of method for the impact of mini-frac blocking agent gel-forming property according to claim 1 is characterized in that, in the described step (a), by clear water configuration pressure break blocking agent solution.
4. a kind of method for the impact of mini-frac blocking agent gel-forming property according to claim 1 is characterized in that in the described step (d), probe temperature is 85 ℃.
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| Application Number | Priority Date | Filing Date | Title |
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| CN 201110325986 CN103048423A (en) | 2011-10-13 | 2011-10-13 | Method for testing influence on gelatinizing property of fracture plugging agent |
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| Application Number | Priority Date | Filing Date | Title |
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| CN 201110325986 CN103048423A (en) | 2011-10-13 | 2011-10-13 | Method for testing influence on gelatinizing property of fracture plugging agent |
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| CN103048423A true CN103048423A (en) | 2013-04-17 |
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Application publication date: 20130417 |